Table 3.

Plasma nicotine and cotinine levels in after treatment with methoxsalen or vehicle in chronically nicotine-treated mice. Mice were injected with vehicle or methoxsalen (15 mg/kg, i.p.) 15 min before nicotine (2 mg/kg, s.c.), three times daily for 4 days. On day 5, mice received one last nicotine dose and 1 h later, blood was collected and nicotine and cotinine plasma levels were measured. Data are expressed as mean ± S.E.M. of n=6 mice/group.

Treatment	Nicotine Levels (ng/ml)	Cotinine Levels (ng/ml)
Vehicle-treated group	32 ± 7	144 ± 9
Methoxsalen-treated group	108 ± 8*	38 ± 6*

^*p<0.05 vs vehicle-treated group.